A method for producing a piston is known from the German patent applications 10 2011 013 141 A1 and DE 10 2011 013 067 A1, in which method the blank of the piston main body is finished by forging in the entire region of the combustion depression. The contour of the combustion depression is thus not involved in the secondary machining process.
It has however been found that the local heating of the piston body during the welding of the blanks results in a change in the microstructure and the dissipation of stresses in the material, which have the effect that the geometry and thus the volume of the combustion depression change. Therefore, the volume of the combustion depression in the finished piston may deviate considerably from the predefined values. Since the combustion depression is finished by forging, additional cutting machining is no longer possible. This applies in particular to combustion depressions with complex geometries.